But-ler, trulliad, heilyn
But-ter, ymenyn
But-ton, botwm: botymu
But-tress, atteg: attegu
By-law, deddf leol; gogyfraith
By-street, heol gefn, coegheol
Cab-bage, bresych, cawl: bresychu; darnguddio
Cab-in, caban, cell, lluest
Ca-ble, rhaff angor
Ca-dence, gostyngiad; goslef: seinamrywio